Effect of exercise training on skeletal muscle histology and
metabolism in peripheral arterial disease.
Hiatt, William R., Judith G. Regensteiner, Eugene E. Wolfel, Michael
R. Carry, and Eric P. Brass.
Department of Medicine, Section of Vascular Medicine (WRH, JGR),
the Division of Cardiology (EEW), and the Department of Neurology
(MRC), University of Colorado Health Sciences Center, Denver, CO
80262; and the Department of Medicine (EPB), Harbor-UCLA Medical
Center, Torrance, CA, 90509
APStracts 3:0214A, 1996.
Patients with symptomatic peripheral arterial occlusive disease (PAOD)
have a claudication-limited peak exercise performance that is
improved with exercise training. The effects of training on skeletal
muscle metabolism were evaluated in 26 patients with claudication,
randomized into a 12 week program of treadmill training (enhances
muscle metabolic activity in normals), strength training (stimulates
muscle hypertrophy in normals), or a non-exercising control group.
Gastrocnemius muscle biopsies were performed at rest, before and
after training. After 12 weeks, only treadmill training improved peak
exercise performance and peak oxygen consumption. Treadmill training
did not alter type I or type II fiber area, and did not increase
citrate synthase activity, but was associated with an increase in the
percent of denervated fibers (from 7.6+/-5.4% to 15.6+/-7.5%,
P<0.05). Improvement in exercise performance with treadmill
training was associated with a correlative decrease in the plasma (r
= -0.67) and muscle (r = -0.59) short-chain acylcarnitine
concentrations (intermediates of oxidative metabolism). Patients in
the strength and control groups had no changes in muscle histology or
carnitine metabolism, but strength trained subjects had a decrease in
citrate synthase activity. Thus, treadmill training increased peak
exercise performance, but this benefit was associated with skeletal
muscle denervation, and the absence of a "classical"
mitochondrial training response (increase in citrate synthase
activity). The current study confirms the relationship between
skeletal muscle acylcarnitine content and function in PAOD,
demonstrating that the response to treadmill training was associated
with parallel improvements in intermediary metabolism.
Received 17 October 1995; accepted in final form 22 March 1996.
APS Manuscript Number A1120-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 1 May 96